Treatment of organic compounds



'rnea'rnr or became COMPOUNDS Wendell W. Meyer, Decatur, ml" assignor to The Solvay Process Company, New York, N. 12., a

corporation of New World No Mil-airing, Application February 23, 1939, Serial No. 25%393 9 @ialms. (6311. 260-6417) This invention relates to a process of treating industrial mixtures of organic compounds containing unsaturated organic compounds (i. e., open-chain and cyclic aliphatic organic compounds including such aliphatic compounds containing arylsubstituents, which compounds contain at least one aliphatic c=o linkage) and other organic compounds, such as saturated aliphatic compounds and aromatic compounds, to convert the unsaturated compounds into products having physical properties and chemical characteristics such that they may be eiifectively separated from the other organic compounds, which are substantially unaflected by the treatment. It particularly relates to a process in which industrial mixtures comprising unsaturated hydrocarbons (i. e., non-aromatic hydrocarbons) in admixture with saturated aliphatic hydrocarbons and/or aromatic hydrocarbons and/or naphthene hydrocarbons (e. g., mixtures such as are obtained by cracking petroleum) are treated to convert the unsaturated hydrocarbons to products having difierent physical properties and chemical characteristics from those of the parent unsaturated hydrocarbons and other components of the mixtures while leaving the saturated hydrocarbons and/or aromatic hydrocarbons and/or naphthene hydrocarbons substantially unafiected, and the conversion products are then separated from the remainder of the mixture.

industrial mixtures comprising unsaturated organic compounds in admixture with other organic compounds, such as saturated aliphatic compounds and aromatic compounds, are ireduently encountered in the chemical and petroleum industries, and it is often desirable to separate the unsaturated compounds from the remainder of these compositions. These industrial mixtures include such naturally occurring mixtures as the fats and oils of vegetable and animal origin and mixtures resulting from various types of physical and chemical processing. Particularly important examples of such mixtures are petroleum fractions, especially cracked petroleum fractions such as cracked gasolines, which comprise unsaturated aliphatic hydrocarbons (i. e., olefines) in admixture with paratfin hydrocarbons and also usually a proportion of aromatic hydrocarbons and naphthene hydrocarbons, depending upon the source of the petroleum. For some purposes it is desirable to make use of the unsaturated compounds in compositions of the above type to the exclusion of the other compounds contained therein, while for other purposes it is desirable to make use of only the other compounds. The separation of the unsaturated compounds from the remainder of such compositions by ordinary methods such as, for example. distillation, selective solvent action, and the like, is often difficult because in general the unsaturated compounds and the remaining compounds in such mixtures have very similar physical properties, such as boiling points and soiubilities in various solvents.

The process of the present invention comprises as its essential step the treatment of industrial mixtures comprising unsaturated organic compounds in admixture with other organic compounds, such as saturated aliphatic compounds.

and aromatic compounds, with nitrosyl chloride or nitrosyl bromide to form between the unsaturated compounds and the nitrosyl chloride or nitrosyl bromide addition products while leaving the other organic compounds substantially uni-- affected. The addition products formed in this way can then be separated from the remainder of the compositions in any suitable or desired manner such as, for example, by distillation or by the action of selective solvents.

Thus it has been found that mixtures comprising unsaturated hydrocarbons in admixture with saturated aliphatic hydrocarbons and/or aromatic hydrocarbons and/or naphthene hydrocarbons can be reacted with nitrosyl chloride to form addition products between the unsaturated hydrocarbons and the nitrosyl chloride While leaving the other compounds in the compositions substantially unafiected, and that these addition products can be separated from the remainder oi the compositions. The invention is based upon the discovery that the reactivity of unsaturated organic compounds, and particularly uncompounds substantially unafiected. It is also based on the discovery that the physical properties and chemical characteristics of the addition products are sumciently different from the properties of the parent compounds that eficient separations can be eiiected to obtain, on the one hand. the addition products as such or chemical derivatives thereof and, on the other hand, the other compounds making up these compositions.

The process of the invention may be employed to accomplish varied results. For example, it may be employed for treating mixtures containing unsaturated compounds to obtain therefrom the unsaturated compounds in the form of addition products or products into which the addition products may be converted by further chemical reaction, all of which products are capable of a number of chemical reactions and therefore are raw materials for use in the preparation of a variety of chemical compounds. Also, the .process may be employed for the purpose of freeing mixtures from unsaturated compunds. Thus the process may be used for the purification of petroleum fractions containing oleflnes to remove therefrom the oleflnes, which are undesirable components in fractions intended for particular purposes. In this way petroleum fractions high in paramn or aromatic content can be obtained. Petroleum fractions free from olehnes are of particular value for use in certain chemical processes and are valuable as special fuels, e. g., as fuels for Diesel engines.

The products formed in the process of the invention between an unsaturated compound and nitrosyl chloride, for example, which are referred to above-as addition products, appear to be com- .posed of compounds in which adjacent carbon atoms which formed an unsaturated linkage in the unsaturated compound are attached respectively to a nitroso group and a chlorine atom; i. e., they are nitroso chlorides. Il.' 'he formation of the nitroso chlorides in the reaction is indicated by the appearance of the blue or green color characteristic of these compounds. Tests have indicated that the addition product also comprises alkene dichlorides, other nitroso compounds. and possibly other reaction products of undetermined nature. It appears that the nitroso chlorides as first formed are in most instances relatively unstable and that the greater proportion at least of the nitroso chlorides are converted upon standing to polymeric or isomeric forms such-as chloroximes and dimers of undetermined structure. In speaking of the addition product of unsaturated compounds and nitrosyl chloride in the specification and claims, it will be understood that it is intended to refer to the product before and after conversion of the nitroso chlorides to polymeric or isomeric forms.

The present process can be used for the treatment of industrial mixtures of varied types comprising unsaturated organic compounds (in which term are included open-chain and cyclic aliphatic compounds, such as ordinary aliphatic compounds and aryl-substituted aliphatic compounds, which contain at least one aliphatic linkage) in admixture with other organic compounds, such as saturated aliphatic compounds and aromatic compounds. It is particularly valuable, however, for the treatment of industrial mixtures of hydrocarbons in which the unsatu rated hydrocarbons are either ordinary oleflnes or cyclic oleflnic hydrocarbons, which mixtures mixtures containing substituted compounds which I are adapted for treatment by the present process are mixtures containing only compounds having unreactive substituents; i. e., compounds free from substituents which either defeat or interfere with the formation of satisfactory addition products between the unsaturated compounds and nitrosyl chloride. The hydroxyl group is an example of a reactive substituent which either defeats or interferes with the formation of satisfactory addition products. In brief it may be stated that the process can be used for the treatment of industrial mixtures of unsaturated and other organic compounds, which compounds are free from reactive substituents; this language being intended to include the hydrocarbon mixtures described above as well as the mixtures containing substituted organic compounds. As examples of substituents that are substantially unreactive with nitrosyl chloride the following are mentioned: halogens, -COOR, --COOH, -COCl, COBr, NR2, -CONR2. CN, --OR. In these formulae, R represents an alkyl, aralkyl, or aryl group. In treating industrial mixture: contain? ing compounds having COOH groups with nitrosyl chloride, these groups are converted largely to -COC1 groups, but this does not interfere with the formation of satisfactory addition products, although in treating such mixtures additional nitrosyl chloride is consumed.

In practicing the present invention in accordance with a preferred manner of proceeding, using nitrosyl chloride to act on an industrial mixture comprising unsaturated hydrocarbons in admixture with saturated aliphatic hydrocarbons and/or aromatic hydrocarbons and/or naphthene hydrocarbons, the nitrosyl chloride may be brought into contact with the composition in various ways under mild conditions. For example, the nitrosyl chloride can be introduced into the composition as a gas or a liquid or, in cases where a solvent is employed, in solution in the solvent. A convenient method comprises passing gaseous nitrosyl chloride through the composition, which is preferably contained in a vessel of relatively narrow cross-section so that all portions of the composition may come in contact with the nitrosyl'chloride. The amount of nitrosyl chloride used in the process depends primaril on the amount of unsaturated compound in the composition subjected to treatment. In order to form a substantial amount of addition products the amount of nitrosyl chloride used should not be materially less than one-half mol for each mol of unsaturated compound. If maximum conversion of the unsaturated compounds to addition products is desired, two or more mole of nitrosyl chloride may be used. Under most conditions it has been found that the use of one to two mols of nitrosyl chloride for each mo] of unsaturated compound produces satisfactory results.

The conditions, such as the temperature, the partial pressure of nitrosyl chloride, the time, and the like, under which the present process is carried out may be varied widely. However, these conditions in each case, taken together, should be relatively mild. This is because, while it has been found that under mild conditions the rate of reaction of unsaturated hydrocarbons with nitrosyl chloride is materially different from the rates of reactions of other compounds, such as saturated aliphatic hydrocarbons and aromatic hydrocarbons, with this reagent so that under these conditions reaction on the unsaturated hydrocarbons occurs while leaving the other compounds substantially unaffected, under relatively drastic conditions an undesirable amount of attack on the other compounds takes place. The optimum conditions for carrying out the process each case will vary depending upon a number factors including the apparatus employed, the acids unsaturated compound or compounds esent in the mixture being treated, the other mpounds present in the mixture, the ratio of e unsaturated compounds to the other comund or compounds in the composition, and the In view of the above considerations it will be iliaed that the specific operating conditions 1 ilch should be employed in the various applicauns oi the present process cannot be definitely lbed. Below there is given, however, a discussnoi the effect of variations in the several crating conditions which indicates the ways in rich the process may be controlled so as to give tisiactory results in particular cases.

The temperature maintained during the proc- 5 has an important eflect upon the efliciency th which the process is operated. It has been and that an increase in temperature increases e rate of reaction of nitrosyl chloride with satated aliphatic hydrocarbons and aromatic hyocarbons as well as with unsaturated hydrocarns and that at temperatures suiiiciently high bstantial attack on saturated aliphatic hydro- .rbons and aromatic hydrocarbons takes place.

3 high temperatures nitrosyl chloride tends to ssociate into a mixture of chlorine and nitric :ide, of which the chlorine acts on the saturated 3o lphatic hydrocarbons and aromatic hydrocarins; this mixture also does not form nitrosyl doride addition products. Accordingly, it has aen found that the upper temperature limit iould not exceed the point at which the efiect the dissociation of nitrosyl chloride becomes ipreciable. Also, it is desirable to lreep the :mperatureat a relatively low point because at lgh temperatures the addition products become ostable. In order to avoid excessive attack on 1e saturated and/or aromatic compounds and [so the thermal decomposition of the addition roducts, it has been found that the reaction iould he carried out at a temperature not above l C. and preferably at a temperature not above 3 C. On the other hand, because the reaction rite of nitrosyl chloride even with unsaturated ydrocarbons becomes excessively low at very aw temperatures, in most cases it is inadvisable i employ temperatures below 20 C. For many so urposes it has been found that temperatures lthin the limits of about 0 to about 40 C. are atisiactory. i

The partial pressure of nitrosyl chloride in the suction vessel is also a factor which should be alren into consideration in carrying out the access efiiciently. It has been found that the reaction proceeds best at relatively low partial lI'ESSIHES or nitrosyl chloride. For example, the eaction is preferably carried out at atmospheric 6) lressure, at which pressure the partial pressure d nitrosyl chloride is equal to or below one atnosphere. Even in cases where the total presure is above atmospheric the partial pressure of iitrosyl chloride i preferably not materially g5 tbOVB one atmosphere. The only cases in which 'rotal reaction pressures abov atmospheric aprear to be desirable are those in which relatively rolatile industrial mixtures are subjected to areatment.

The period of time during which contact he- ;ween the nitrosyl chloride and the mixture sublected to treatment should be maintained to achieve optimum results depends so greatly upon partial pressure of nitrosyl chloride, the specific nature 01' the components or the mixture, and the like, that abmlute time limits cannot be stated. For example, at relatively high temperatures a short reaction period is desirable while at low temperatures a long reaction time is required in order to permit reaction between the nitrosyl chloride and the imsaturated compounds. In this connection it should be noted that the reaction should not be continued beyond the time necessary to give the desired percentage attack on the.gunsaturated compounds as further reaction by nitrosyl chloride may result in attack to some extent on-other compounds in the mixture.

It will be understood that the value of the present process will vary depending upon the specific industrial mixtures subjected to treatment. Thus mixtures containing relatively unreactive unsaturated compounds and relatively reactive saturated compounds must be subjected to careful treatment in order to effect reaction between the nitrosyl chloride and the unsaturated compounds while avoiding reaction with the other compounds in the mixtures. In this connection it has been i'ound that terminal bond olefines react less readily than non-terminal bond oleflnes. (As employed through this description and in the claims, the term olefines" means open-chain aliphatic hydrocarbons which contain at least one aliphatic c= linkage.) On the other hand, ithas been found that paraflin hydrocarbons containing a tertiary carbon atom are more reactive than those containing only secondary and primary carbon atoms.

The present process can be efilciently carried out in glass apparatus in the presence of such light as is normally present in a laboratory or plant. However, in order to obtain maximum selective action of nitrosyl chloride on the unsaturated compounds present in the mixture subjected to treatment, it is advisable to carry out the process so as to avoid the reaction mixture coming into contact with direct light, particularly direct sunlight.

After the formation of addition products be- .tween the unsaturated compounds present in the industrial mixtures subjected to treatment has been completed there is obtained a mixture comprising the addition products and the other compounds present in the original mixture, usually together with asmall proportion of unreacted unsaturated compounds. The separation of the addition products from the remainder of the mixtures may be effected in a number of ways, the most eificient manner of operation depending in each case upon the nature of the mixture. For example, in cases where the boiling points of the addition products and the other compounds in the compositions are sufiiciently difierent, separation may be efiected by distillation; for example,

vacuum or steam distillation. In certain cases, efiicient separation has been found to be possible by simple filtration, due to the fact that the addition products appear as crystalline substances in the reaction mixtures. .Also, the separation may be efiected with the use of solvents in which the addition products and the remainder of the mixtures have different solubilities. The separation may be also efiected by subjecting the addition products to chemical action whereby they are converted to products easily separated from has other factors, such as the temperature, the the remainder of the mixtures. A particularly eilective manner of carrying out the separation in accordance with this general manner of procedure is that described in U. S. Patent 2,265,993 to L. J. Beckham. As described in that patent, mixtures of the type under consideration can be reacted with an aqueous solution of an alkali metal sulfite, such as sodium sulfite, to convert the addition products to water-soluble compounds which can be easily separated from the water-insoluble remainder of the mixtures.

The following examples, in which the parts are by weight, serve to illustrate the invention:

Example 1 106 parts of a mixture of hydrocarbons consist ing of 84 per cent benzene and 16 per cent cyclohexene, by weight, are introduced into a vessel im mersed in an ice bath. 13 parts of nitrosyl chloride are then added slowly to the mixture. The temperature of the resulting reaction mixture rises to 45 C. in fifteen minutes, after which time the reaction product is distilled. The distillation is carried out so as to remove substantially all the benzene at temperatures around 80 C. At tem-.

peratures above this point a small amount of a dark blue addition product is separately collected, leaving in the distillation vessel a partially decomposed addition productof nitrosyl chloride and cyclohexene.

Example 2 Example 3 46,302 parts of a paraflin wax having a melting point of 123 to 125 F. are cracked in the liquid phase in a steel still at one atmosphere.

1170 parts of a close-cut fraction, boiling point 175 to 200 C. at atmospheric pressure, are obtained from the resulting cracked product. This Y fraction consists of approximately 56 per cent olefines, and 44 per cent paramns. 205 parts of this fraction are treated with 98 parts of nitrosyl chloride, the nitrosyl chloride being passed vessel adapted to cause intimate contact between the mixture and the nitrosyl chloride. The rethrough the hydrocarbon mixture contained in a -;t'-

action is carried out at a temperature of 25 C.

The nitrosyl chloride is passed through the hyv drocarbon mixture for 7% hours and the mixture is allowed to stand overnight giving a total contact time of 23 hours. a

This mixture of hydrocarbons and olefine addition products is treated in the manner described in U. S. Patent 2,265,993 to Beckham. Thus, this mixture is added to a solution made up of 302 parts of anhydrous sodium sulfite and 900-parts of water. The temperature is raised to 100 C. and the mixture is stirred at this temperature for 24 hours. At the end of this period the mixture is diluted with water and the aqueous and nonaqueous phases are separated. Some diethylether is added to facilitate this separation. The

nitrosyl chloride-olefine addition product is soluasaasos bilized by this treatment and a major fraction thereof is present in the aqueous phase. The unreacted hydrocarbon portion is recovered by evaporation of the ether. The aqueous phase is evaporated to recover water-soluble compounds obtained from the olefines present in the material subjected to' treatment. v Example 4 A mixed material consisting of 25 parts of a nitrosyl chloride-oleflne addition product of a terminal bond liquid oleflne oi the formula Cams and 25 parts of non-oleflnic petroleum hydrocarbons of approximately the. same boiling range is extracted at 25 C. with two successive portions of glacial acetic acid of parts each to obtain a solution containing the bulk of the addition product in acetic acid. On boiling oil the acetic acid from the acetic acid solution under diminished pressure, a nitrosyl chloride-olefine addition product is obtained.

" Example 5 109 parts of a distillate fraction obtained from.

the cracking of a Pennsylvania crude petroleum containing approximately 28 per cent olefines, 16'per cent aromatics, 15 per cent naphthenes,

and 41 per cent parafilns, is treated with 9.8 parts of nitrosyl chloride at 25 C. for two hours in a vent), and most of the nitrosyl chloride-oleflne addition product is present in the lower layer. The addition product is recovered by evaporating off the solvent.

Example 6 50 parts of the initialmixture of Example 4 are extracted at room temperature with 184 parts of concentrated sulfuric acid. The resulting sulfuric acid solution contains substantially all of the nitrosyl chloride-olefine addition product. The remaining insoluble material is washed with water and dried; its refractive index and density indicate it to be substantially pure hydrocarbon.

In the above discussion and examples, the use of nitrosyl chloride has been stressed since this. reagent is preferred for both economic and technical reasons over nitrosyl bromide. However, the invention also includes the use of the latter reagent in a manner similar to thatdescribed in connection with nitrosyl chloride.

The mixtures obtained as a result of the treatment of industrial mixtures with nitrosyl chloride or nitrosyl bromide in accordance with the present process are valuable compositions which can be used as raw materials for the production of a variety of chemical products. Such mixtures form a part of the present invention.

Since certain changes may be made in carrying out the above-described process without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

linkage but are free from reactive substituents in admixture with other organic compounds free from reactive substituents, which comprises reacting said industrial mixture with a nitrosyl halide selected from the group consisting of nitrosyl chloride and nitrosyl bromide under mild conditions to form a resulting mixture comprising addition products of said unsaturated organic compounds and said nitrosyl halide, while leaving said other organic compounds substantially unaffected, and separating said addition products from the remainder of said resulting mixture.

2. The process for the treatment of an industrial mixture comprising unsaturated organic compounds which contain an aliphatic linkage but are free from reactive substituents in admixture with other organic compounds free from reactive substituents, which comprises reacting said industrial mixture with nitrosyl chloride under mild conditions to form a resulting mixture comprising addition products of said unsaturated organic compounds and said nitrosyl chloride, while leaving said other organic compounds substantially unaffected, and separating said addition products from the remainder of said resulting mixture.

3. The process for the treatment of an industrial mixture comprising unsaturated hydrocarbons which contain an aliphatic I I C=C linkage in admixture with hydrocarbons selected from the group consisting of saturated aliphatic hydrocarbons, aromatic hydrocarbons, and naphthene hydrocarbons, which comprises reacting said industrial mixture trial mixture comprising unsaturated hydrocarbons which contain an aliphatic linkage in admixture with hydrocarbons selected from the group consisting of saturated aliphatic hydrocarbons, aromatic hydrocarbons, and naphthene hydrocarbons, which comprises reacting said industrial mixture with nitrosyl chloride under mild conditions including a temperature of below 80" C. to forma resulting mixture comprising addition products of said unsaturated hydrocarbons with said nitrosyl chloride, while leaving said other hydrocarbons substantially unaffected, and separating said addition products from the remainder of said resulting mixture. 6. The process for the treatment of an industrial mixture comprising unsaturated organic compounds which contain an aliphatic with a nitrosyl halide selected from the group consisting of nitrosyl chloride and nitrosyl bromide under mild conditions to form a resulting mixture comprising addition products of said unsaturated hydrocarbons with said nitrosyl halide, while leaving said other hydrocarbons substantially unaifected, and separating said addition products from the remainder of said resulting mixture.

4. The process for the treatment of an industrial mixture comprising unsaturated hydrocarbons which contain an aliphatic linkage but are free from reactive substituents in admixture with other organic compounds free from reactive substituents, which comprises reacting saidindustrial mixture with nitrosyl chloride at a temperature between -20 and 60 C. and at atmospheric pressure to fOrm a resulting mixture comprising addition products of said unsaturated organic compounds and said nitrosyl chloride, while leaving said other organic com pounds substantially unaffected, and. separating said addition products from the remainder of said resulting mixture.

7. The process for the treatment of a petroleum fraction containing olefines in admixture with other hydrocarbons to reduce the olefine content thereof, which comprises reacting said fraction with nitrosyl chloride at a temperature between -20 and 60 C. and at atmospheric pressure to form a resulting mixture comprising addition productsof said olefines and said nitrosyl chloride, and separating said addition products from the remainder of said resulting mixture.

8. The process for the treatment of a petroleum fraction containing oleflnes in admixture with other hydrocarbons to reduce the olefine content thereof, which comprises reacting said fraction with nitrosyl chloride at a temperature between 0 and 40 C. and at atmospheric pressure to form a resulting mixture comprising addition products of said olefines and said nitrosyl chloride, and separating said addition products by distillation from the remainder of said resulting mixture.

9. The process for the treatment of an industrial mixture comprising unsaturated organic compounds which contain an aliphatic linkage but are free from reactive substituents in admixture with other organic compounds free from reactive substituents, which comprises reacting said industrial mixture with a nitrosyl halide selected from the group consisting of nitrosyl chloride and nitrosyl bromide under mild conditions including a temperature of below C. to :l'orm a resulting mixture comprising addition products of said unsaturated organic compounds and said nitrosyl halide, while leaving said other organic compounds substantially unafiected, and separating said addition products from the remainder of said resulting mixture.

WENDELLW. MOYER. 

